US20210328185A1 - Light-emitting devices with improved light outcoupling - Google Patents

Light-emitting devices with improved light outcoupling Download PDF

Info

Publication number
US20210328185A1
US20210328185A1 US17/302,759 US202117302759A US2021328185A1 US 20210328185 A1 US20210328185 A1 US 20210328185A1 US 202117302759 A US202117302759 A US 202117302759A US 2021328185 A1 US2021328185 A1 US 2021328185A1
Authority
US
United States
Prior art keywords
domain
optoelectronic device
sub
domains
inorganic barrier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US17/302,759
Other versions
US11793024B2 (en
Inventor
Florian Pschenitzka
Christopher D. Favaro
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kateeva Inc
Original Assignee
Kateeva Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kateeva Inc filed Critical Kateeva Inc
Priority to US17/302,759 priority Critical patent/US11793024B2/en
Publication of US20210328185A1 publication Critical patent/US20210328185A1/en
Assigned to SINO XIN JI LIMITED reassignment SINO XIN JI LIMITED SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KATEEVA CAYMAN HOLDING, INC., KATEEVA, INC.
Assigned to HB SOLUTION CO., LTD. reassignment HB SOLUTION CO., LTD. SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KATEEVA CAYMAN HOLDING, INC.
Priority to US18/464,130 priority patent/US20230422545A1/en
Application granted granted Critical
Publication of US11793024B2 publication Critical patent/US11793024B2/en
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80Constructional details
    • H10K59/87Passivation; Containers; Encapsulations
    • H10K59/873Encapsulations
    • H10K59/8731Encapsulations multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00Organic light-emitting devices
    • H10K50/80Constructional details
    • H10K50/84Passivation; Containers; Encapsulations
    • H10K50/844Encapsulations
    • H01L51/5253
    • H01L51/5275
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00Organic light-emitting devices
    • H10K50/80Constructional details
    • H10K50/85Arrangements for extracting light from the devices
    • H10K50/858Arrangements for extracting light from the devices comprising refractive means, e.g. lenses
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80Constructional details
    • H10K59/875Arrangements for extracting light from the devices
    • H10K59/879Arrangements for extracting light from the devices comprising refractive means, e.g. lenses
    • H01L2251/303
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00Constructional details relating to the organic devices covered by this subclass
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80Constructional details
    • H10K59/875Arrangements for extracting light from the devices
    • H10K59/877Arrangements for extracting light from the devices comprising scattering means

Definitions

  • Multilayered encapsulation stacks composed of alternating inorganic and organic polymer films have been used to protect light-emitting devices from the damaging effects of exposure to water vapor and oxygen.
  • RI refractive index
  • the difference between the refractive index (RI) of an inorganic layer in the stack and its neighboring lower refractive index organic polymer layer can result in total internal reflection of the light at the interface between the two layers, which reduces the fraction of light able to exit the device.
  • light-emitting devices can suffer from limited light output due to total internal reflection of light at the interface between the terminal layer in an encapsulation stack and on overlying device layer or, in the absence of on overlying device layer, at the interface between the terminal layer in an encapsulation stack and air.
  • the inventions described herein relate to encapsulation stacks and light-emitting devices, such as organic light-emitting diode (OLED) devices that include the multilayered encapsulation stacks.
  • the multilayered encapsulation stacks provide reduced total internal reflection and, therefore, improved light output efficiencies relative to conventional encapsulation stacks.
  • FIG. 1A is a schematic diagram showing a cross-sectional view of one embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which a single high refractive index dome-shaped structure is disposed over each sub-pixel of the device.
  • FIG. 1B is a top view of the OLED device.
  • FIG. 2 is a schematic diagram showing a cross-sectional view of a second embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which a single high refractive index cylindrical structure is disposed over each sub-pixel of the device.
  • FIG. 3 is a schematic diagram showing a cross-sectional view of one embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which multiple high refractive index dome-shaped structures are disposed over each sub-pixel of the device.
  • FIG. 4 is a schematic diagram showing a top view of another embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which multiple high refractive index dome-shaped structures are disposed over each sub-pixel of the device.
  • FIG. 5A is a schematic diagram showing a cross-sectional view of an OLED device having a composite film at the top of its multilayered encapsulation stack.
  • FIG. 5B is a schematic diagram showing the multilayered encapsulation stack of FIG. 5A in greater detail.
  • FIG. 6 is a schematic diagram of a method of making the OLED device of FIG. 1A and FIG. 1B .
  • FIG. 7 is a schematic diagram of a method of making the OLED device of FIG. 2 .
  • the devices described herein include various electronic and optoelectronic devices in which an active region of the device is encapsulated with a protective multilayered encapsulation stack.
  • the “active region” need not meet any requirement of amplification of electrical energy or transistor activity, and can refer generally to a region wherein electrical or optoelectrical activity (e.g., light emission, light absorption, or light conversion) can occur.
  • the active region will itself generally be a multilayered structure composed of a plurality of device layers including, for example, electrodes, charge injection layers, charge transport layers, and/or light-emitting layers.
  • the encapsulation stacks can be applied to other light-emitting devices, including other top-emitting lighting devices, top-emitting quantum dot (QD)-LED devices, micro-LED displays and QD-photoluminescent (PL) emissive color converters.
  • this technology can be applied to photosensors and photocells where a high amount of light coupled into the device is advantageous.
  • FIG. 1A A schematic diagram shown a cross-sectional view of one embodiment of an OLED device 100 that includes a multilayered encapsulation stack is depicted in FIG. 1A .
  • FIG. 1B A top view of the OLED device is shown in FIG. 1B .
  • This embodiment of an OLED device includes a plurality of active regions 104 and an OLED device substrate 102 .
  • a multilayered encapsulation stack 106 is disposed over active regions 104 .
  • Multilayered encapsulation stack 106 which protects underlying active regions 104 from degradation from exposure to air and/or moisture, includes a first inorganic barrier layer 108 that suppresses the exposure of the active regions 104 to water vapor, oxygen, and/or other reactive gases present in the ambient atmosphere.
  • first inorganic barrier layer 108 Adjacent to first inorganic barrier layer 108 is a composite film 109 that includes a first domain comprising a first polymeric layer 110 .
  • First polymeric layer 110 is composed of one or more organic polymers and provides a planarization layer to planarize the encapsulation stack.
  • multilayered encapsulation stack 106 includes a second inorganic barrier layer 108 A disposed over composite film 109 .
  • the order of the layers could be reversed, so that the composite film 109 is first fabricated, followed by the fabrication of first inorganic barrier layer 108 .
  • a second planarizing polymeric layer and a second inorganic barrier layer could then be deposited, sequentially, in order to provide sufficient encapsulation for the underlying device.
  • a modified process includes the deposition of composite film 109 directly on top of an active region of a device, followed by the deposition of a first inorganic barrier layer, followed by the deposition of a second polymeric layer, followed by the deposition of a second inorganic barrier layer.
  • more or fewer numbers of inorganic barrier layers and polymeric layers can be provided.
  • the encapsulation stack of FIG. 1A could have a second polymeric layer disposed on second inorganic barrier layer 108 A. Active regions 104 of the OLED device of FIG.
  • each of these sub-pixels may include an organic light-emitting layer disposed between a first electrode (e.g., a cathode) and a second electrode (e.g., an anode).
  • a first electrode e.g., a cathode
  • a second electrode e.g., an anode
  • an electron transport layer and/or an electron injection layer may be disposed between the cathode and the light-emitting layer and a hole transport layer and/or a hole injection layer may be disposed between the anode and the light-emitting layer.
  • At least one layer in the encapsulation stack is a composite film that includes a first domain formed from a first polymer and a second domain formed from a second polymer, wherein the second domain has a higher RI than the first domain and further wherein the second domain desirably has an RI that is the same as, or nearly the same as, the RI of the inorganic material of first inorganic barrier layer 108 .
  • the second domain can be a discontinuous domain that includes a plurality of sub-domains that are typically surrounded by or embedded in the first domain.
  • the sub-domains are a plurality of dome-shaped structures 112 .
  • Suitable RIs for sub-domains 112 will depend on the RI of the inorganic barrier layer.
  • the RIs of the sub-domains and the inorganic barrier layers differ by no more that ⁇ 15%, including no more than 10%, and further including no more than 5%.
  • the sub-domains may have an RI of about 1.7 or higher.
  • the material from which the higher RI domain is made can be a polymeric material comprising one or more organic polymers or a polymer composite, including a polymeric material that contains inorganic particles dispersed in a polymer matrix.
  • Suitable polymers include acrylics, urethanes, and epoxies.
  • Suitable inorganic particles include metal oxide particles, such as zirconium oxides, titanium oxides, hafnium oxides, zinc oxides, and mixtures of two or more thereof.
  • the inorganic oxide particles may be surface-functionalized with capping agents that improve their dispersibility in a polymer matrix.
  • Such capping agents may include 2-[2-(2-9-methoxyethoxy)ethoxy] acetic acid and/or methoxy(triethyleneoxy) propyltrimethoxysilane and/or 3 methacryloyloxypropyltrimethoxysilane and/or n-octyl trimethoxysilane and/or dodecyltrimethoxysilane and/or m,p-ethylphenethyl trimethoxysilane.
  • the same metal oxide is present in the higher RI domain of the composite film and the inorganic barrier layer.
  • the high RI polymer-nanocrystal composite materials used in the nanocomposite coatings described in U.S. patent publication number 2014/0322549, the entire disclosure of which is incorporated herein by reference, could be used to form the higher RI domain in the composite films of the multilayered encapsulation stacks described herein.
  • sub-domains 112 provide a non-planar interface between the higher RI material of the sub-domains and the lower RI material of the first domain, so that they change the angle of the light reflected at that interface, such that total internal reflection is suppressed and light outcoupling and extraction is enhanced.
  • the particles may act as scattering centers to further reduce internal reflection and light trapping.
  • the particles may have diameters that are small enough to avoid or minimize light scattering.
  • the sub-domains of the composite films can have a variety of shapes and sizes. For example, as shown in FIG.
  • the sub-domains can be structures, such as hemispheres (domes) arranged in regular array or a random pattern. Once formed, the structures can be covered with a layer of the lower RI polymeric material of the first domain to form a smooth planar, or substantially planar, surface upon which the next inorganic barrier layer can be formed.
  • the sub-domains can be cylinders 114 arranged in a regular array or a random pattern, as shown in FIG. 2 .
  • the first domain 110 surrounds cylinders 114 and the surface formed by first domain 110 and cylinders 114 provides a smooth planar, or substantially planar, surface upon which the next inorganic barrier layer 108 A can be formed.
  • cylindrical structures can be beneficial because light reflected at the vertical interfaces 116 formed between cylindrical sub-domains 114 and first domain 110 can be directed toward the light-emitting surface of the device, further reducing the trapping of light in the first inorganic barrier layer 108 and/or active regions 104 .
  • the dimensions and placement of the sub-domains are not strictly limited, provided that they are able to reduce the total internal reflection within the device.
  • various embodiments of the sub-domains including the hemispherical structures, have radii in the range from 1 ⁇ m to 50 ⁇ m, inter-structure spacings (pitch) in the range from 1 ⁇ m to 100 ⁇ m, and/or heights in the range from 1 ⁇ m to 50 ⁇ m; although dimensions outside of these ranges can be used.
  • the sub-domains can be covered with or laterally encased in a layer of lower RI polymeric material of the first domain to form a smooth planar, or substantially planar, composite film surface upon which the next inorganic barrier layer can be formed.
  • the first domain and the second domain can be formed simultaneous into a composite film having a smooth planar, or substantially planar, surface upon which the next inorganic barrier layer can be formed.
  • the sub-domains can be patterned (e.g., inkjet printed) with a resolution commensurate with the resolution of the display device.
  • there is one sub-domain associated with each pixel or with each sub-pixel within a pixel as illustrated in FIG. 1A , FIG. 1B , and FIG. 2 .
  • the sub-domains are much smaller than the pixels or sub-pixels, such that a plurality of the sub-domains is disposed over each pixel or sub-pixel.
  • the sub-domains can be localized in clusters over each pixel or sub-pixel in a display device.
  • FIG. 3 shows a cross-sectional view of a portion of a display device including an OLED sub-pixel 304 over which an encapsulation stack 306 is disposed.
  • Encapsulation stack 306 includes a first inorganic barrier layer 308 , a composite film 309 comprising a first domain 310 , a second domain comprising a plurality of dome-shaped sub-domains 312 clustered over OLED 304 , and a second inorganic barrier layer 308 A over composite film 309 .
  • FIG. 4 shows a top view of three sub-pixels (red (R), green (G), and blue (B)), each of which is associated with three overlying sub-domain 412 of a composite film.
  • An advantage of implementing the composite film on top of the first (i.e., lowermost) inorganic barrier layer in a multilayered encapsulation stack, rather than at the top of the encapsulation stack, is that such placement reduces the distance between the light-emitting layer of the sub-pixels and the high RI sub-domains of the composite film. This is advantageous because it helps to reduce color bleeding, which can decrease the perceived resolution, the black contrast, and/or the color gamut of the OLED display.
  • the composite film in the device embodiments shown in FIG. 1A , FIG. 1B , and FIG. 2 is positioned directly on the first inorganic barrier layer of the encapsulation stack
  • the composite film can be formed on a second (or higher) inorganic barrier layer within the encapsulation stack.
  • the composite film can be placed on the top inorganic barrier layer of an encapsulation stack, as shown in the OLED device depicted in FIG. 5A and FIG. 5B .
  • composite films can be provided on more than one inorganic barrier layer in a multilayered encapsulation stack.
  • the composite film can be placed directly on the top surface of the underlying active regions (for example, on the top electrode of an OLED stack to provide the first layer of the encapsulation stack.
  • all of the layers in the encapsulation stack underlying the composite film, including the polymeric planarization layers, should be made of high RI materials.
  • the underlying planarization layers can have the same material composition as the second domain in the composite film.
  • the planarization layers and the second domain of the composite film need not have the same composition, provided that the planarization layers have an RI that is the same as, or nearly the same as (e.g., differing by no more than 15%), the RI of the inorganic materials of inorganic barrier layers in the encapsulation stack.
  • the high RI planarization layers may have an RI of about 1.7 or higher.
  • FIG. 5A An embodiment of an OLED display device that includes a composite film as the final layer of an encapsulation stack is illustrated schematically in FIG. 5A .
  • This figure is a cross-sectional view and includes the components of the active region 530 of an OLED device. These include a reflective anode 522 , an organic layer stack 524 , and a semi-transparent cathode 526 . Over active region 530 is disposed an encapsulation stack 506 and a top protective glass layer 528 .
  • Organic layer stack 524 may include, from top to bottom, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer.
  • the OLED device may further include a support substrate 520 .
  • the final layer of encapsulation stack 506 comprises a composite film 509 of the type described herein, disposed over the other, underlying encapsulation stack layers 511 (shown here as a single block for simplicity).
  • FIG. 5B shows a more detailed cross-sectional view of encapsulation layer 506 with upper composite film 509 .
  • This composite film has a structure similar to that shown in FIG. 3 , with the exception that composite film 509 is at the top of the encapsulation stack and the underlaying layers of the encapsulation stack include one of more inorganic barrier layers 507 comprising a high RI material, which may be same material from which sub-domains 512 are formed.
  • a composite film that includes a high RI domain within the layers of an encapsulation stack can significantly enhance the light extraction efficiency and the integrated current efficiency of an OLED device that incorporates the film, relative to an OLED device that does not include such a film, but is otherwise the same.
  • various embodiments of the encapsulation stacks in accordance with the present teachings increase the extraction efficiency of an OLED device by at least 30% (e.g., by 30% to 40%) and the integrated current efficiency of an OLED device by at least 70% (e.g., by 70% to 100%).
  • encapsulation stacks that include the composite films can reduce the viewing angle dependence of the emitted light, resulting in a higher quality display.
  • Examples of inorganic materials useful for fabricating inorganic barrier layers of a multilayered encapsulation stack can include, for example, various nitrides, oxides, and oxynitrides, such as one or more of silicon nitrides (SiN x ), silicon oxides, Al 2 O 3 , TiO 2 , HfO 2 , and silicon oxynitrides (SiO x N y ).
  • the inorganic barrier layers can be deposited or otherwise formed over active regions and may be blanket coated (e.g., via chemical and/or physical vapor deposition) over the entirety, or substantially the entirety of the exposed surface of a substrate and active regions.
  • Polymers useful for fabricating the first and second domains of the composite films and the other polymeric planarizing layers of a multilayered encapsulation stack include various polymer materials that are curable using one or more of a thermal (e.g., bake), radiation (e.g., ultraviolet exposure), or other energy-based (e.g., electron beam) curing technique, and once cured can form a polymeric thin film and/or polymeric structure.
  • a thermal e.g., bake
  • radiation e.g., ultraviolet exposure
  • other energy-based (e.g., electron beam) curing technique e.g., electron beam
  • the polymeric layers of the encapsulation stack, including the composite film are formed by inkjet printing an ink composition comprising curable monomers, oligomers, and/or polymers onto a substrate (e.g., onto an inorganic barrier layer) and curing the composition to form a polymer film.
  • the ink compositions may include one or more crosslinking agents, polymerization initiators, and/or solvents.
  • the polymeric planarization layers can also be made by applying the ink compositions onto a device substrate using coating techniques other than inkjet printing, followed by curing the composition to form a polymer film.
  • Examples of acrylate and methacrylate (collectively referred to herein as (meth)acrylate) monomers that can be included in an ink composition include mono(meth)acrylate monomers, di(meth)acrylate monomers and (meth)acrylate monomers of higher functionality.
  • the (meth)acrylate monomers are polyethers.
  • the (meth)acrylate monomers are alkoxylated aliphatic di(meth)acrylate monomers.
  • neopentyl glycol group-containing di(meth)acrylates including alkoxylated neopentyl glycol diacrylates, such as neopentyl glycol propoxylate di(meth)acrylate and neopentyl glycol ethoxylate di(meth)acrylate.
  • suitable (meth)acrylate monomers include, but are not limited to: alkyl (meth)acrylates, such as methyl (meth)acrylate, ethyl (meth)acrylate, and benzyl methacrylate; cyclic trimethylolpropane formal (meth)acrylate; alkoxylated tetrahydrofurfuryl (meth)acrylate; phenoxyalkyl (meth)acrylates, such as 2-phenoxyethyl (meth)acrylate and phenoxymethyl (meth)acrylate; 2(2-ethoxyethoxy)ethyl (meth)acrylate.
  • alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and benzyl methacrylate
  • cyclic trimethylolpropane formal (meth)acrylate alkoxylated tetrahydrofurfuryl (meth)acrylate
  • di(meth)acrylate monomers include 1,6-hexanediol diacrylate, 1, 12 dodecanediol di(meth)acrylate; 1,3-butylene glycol di(meth)acrylate; di(ethylene glycol) methyl ether methacrylate; and polyethylene glycol di(meth)acrylate monomers.
  • DCPOEA dicyclopentenyloxyethyl acrylate
  • ISOBA isobornyl acrylate
  • DCPOEMA dicyclopentenyloxyethyl methacrylate
  • ISOBMA isobornyl methacrylate
  • OctaM N-octadecyl methacrylate
  • the multifunctional (meth)acrylate crosslinking agents desirably have at least three reactive (meth)acrylate groups.
  • the multifunctional (meth)acrylate crosslinking agents can be, for example, tri(meth)acrylates, tetra(meth)acrylates and/or higher functionality (meth)acrylates.
  • Pentaerythritol tetraacrylate or pentaerythritol tetramethacrylate, di(trimethylolpropane) tetraacrylate, trimethylolpropane triacrylate, and di(trimethylolpropane) tetramethacrylate are examples of multifunctional (meth)acrylates that can be used as a primary cross-linking agent.
  • the term ‘primary’ is used here to indicate that other components of the ink compositions may also participate in crosslinking, although that is not their main functional purpose.
  • compositions used to form the nanocomposite coatings in U.S. patent application publication number 2014/0322549 are examples of ink compositions that can be used to form the second domain of the composite films and/or any high RI planarizing layers in the encapsulation stacks.
  • the ink compositions described in U.S. patent application numbers US 20160024322, US 2017/0062762, and US 2017/0358775 are examples of ink compositions that can be used to form the first domain of the composite films and/or other polymeric planarization layers in the multilayered encapsulation stacks.
  • the surface tension, viscosity, and wetting properties of the initial ink compositions should be tailored to allow the compositions to be dispensed through an inkjet printing nozzle without drying onto or clogging the nozzle at the temperature used for printing (e.g., room temperature; ca. 25° C.).
  • the temperature used for printing e.g., room temperature; ca. 25° C.
  • some embodiments of the ink compositions used to form polymeric layers have viscosities of between about 10 cP and about 28 cP (including, for example, between about 15 cP and about 26 cP) at 25° C. and surface tensions of between about 28 dynes/cm and about 45 dynes/cm at 25° C.
  • solvents, surfactants, viscosity modifiers, and the like may be included in the ink compositions.
  • Suitable organic solvents include esters and ethers.
  • the surface energy of the surface onto which the ink composition is deposited can also be modified in order to achieve the desired ink spreading. This can be done by plasma treatment, exposure to gas containing the surface modifiers, and coating of a thin primer layer containing the surface modifiers. It is also possible to deposit these surface modifiers in a patterned fashion and thus force the ink to be pinned at a defined location on the substrate.
  • FIG. 6 A method of making an OLED device of the type shown in FIG. 1A and FIG. 1B is illustrated schematically in FIG. 6 .
  • one or more active regions (e.g., sub-pixels) 104 are formed on device substrate 102 and first inorganic barrier layer 108 is deposited as a film over the active regions.
  • droplets of an ink composition 600 comprising the materials that make up the sub-domains of the composite film are deposited (e.g., inkjet printed) onto first inorganic barrier layer 108 over active regions 104 (panel (a)).
  • the droplets spread on the surface and are cured to form the dome-shaped structures 112 (panel (b)).
  • the composition of the sub-domains can be independently tailored to meet the desired optical properties for the different sub-pixels.
  • pixel banks can be used to confine the spreading ink composition 600 after it is printed.
  • ink composition 600 can be confined by patterning the surface of the substrate upon which it is deposited with hydrophobic and/or hydrophilic regions that control the wetting characteristics of the ink composition.
  • droplets of an ink composition 602 comprising the materials that make up the first, lower RI domain of the composite film are deposited (e.g., inkjet printed) as a coating onto first inorganic barrier layer 108 over higher RI structures 112 (panel (c)).
  • first domain 110 is then cured to form the first domain 110 .
  • second inorganic barrier layer 108 A is deposited as a film over the first polymeric layer that constitutes the first domain of the composite film 109 (panel (d)).
  • the higher RI ink composition 600 is not cured before the deposition of the lower RI ink composition 602 .
  • the two ink compositions are optimized such that they do not intermix, or such that they only partially intermix, so that the outcoupling benefit of the structures in the final device is retained.
  • the ink composition that forms sub-domain structures 112 is cured after deposition, but before the lower RI ink composition 602 that forms the first domain is deposited. In this case the interface between the two cured domains is well defined and abrupt. This approach places fewer constraints on the ink composition system because intermixing between the two ink compositions is suppressed by the curing step.
  • FIG. 7 A method of making an OLED device of the type shown in FIG. 2 is illustrated schematically in FIG. 7 .
  • the ink composition 400 for making the higher RI structures of the sub-domains and the ink composition 602 for making the first domain are designed such that they wet the surface of first inorganic barrier layer 108 similarly to form a planar coating on the surface, but do not substantially intermix within the coating.
  • Droplets of the ink compositions 600 and 602 can be printed (either simultaneously or sequentially) onto first inorganic barrier layer 108 without curing in between the printing steps (panels (a) and (b)) and the coating can then be cured, whereby cylindrical sub-domain structures (or features resembling cones) 114 laterally encased in a polymeric layer of the first domain 110 are formed, followed by the deposition of second inorganic barrier layer 108 A (panel (c)).
  • some intermixing between the ink compositions is allowable, provided that the intermixing zones are relatively small and the RI contrast between the two domains is preserved.
  • An industrial inkjet printing system that can be housed in an enclosure configured to provide a controlled process environment can be used for the deposition of the ink compositions onto a device substrate.
  • Inkjet printing for the deposition of the ink compositions described herein can have several advantages. First, a range of vacuum processing operations can be eliminated, as inkjet-based fabrication can be performed at atmospheric pressure. Additionally, during an inkjet printing process, an ink composition can be localized to cover portions of an OLED substrate over and proximal to an active region, to effectively encapsulate the active region, including lateral edges of the active region.
  • the targeted patterning using inkjet printing results in eliminating material waste, as well as eliminating additional processing typically required to achieve patterning of an organic thin film, as required, for example, by various masking techniques.
  • the ink compositions can be printed using, for example, a printing system, such as described in U.S. Pat. No. 9,343,678.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Electroluminescent Light Sources (AREA)
  • Led Device Packages (AREA)
  • Led Devices (AREA)

Abstract

Optoelectronic devices that include a composite film in a multilayered encapsulation stack are provided. Also provided are methods of forming the light reflection-modifying structures, as well as other polymeric device layers, using inkjet printing. The composite films include a first, lower refractive index domain and a second, higher refractive index domain.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application is a continuation of U.S. nonprovisional patent application Ser. No. 16/771,157, filed on Jun. 9, 2020, which is a National Stage of International Application No. PCT/US18/63492, filed on Nov. 30, 2018, which claims the benefit of U.S. provisional patent application No. 62/607,824, filed on Dec. 19, 2017, the entire contents of which are hereby incorporated herein by reference.
  • BACKGROUND
  • Multilayered encapsulation stacks composed of alternating inorganic and organic polymer films have been used to protect light-emitting devices from the damaging effects of exposure to water vapor and oxygen. Unfortunately, the difference between the refractive index (RI) of an inorganic layer in the stack and its neighboring lower refractive index organic polymer layer can result in total internal reflection of the light at the interface between the two layers, which reduces the fraction of light able to exit the device. Moreover, even in the absence of a high RI mismatch between the inorganic and organic polymer layers, light-emitting devices can suffer from limited light output due to total internal reflection of light at the interface between the terminal layer in an encapsulation stack and on overlying device layer or, in the absence of on overlying device layer, at the interface between the terminal layer in an encapsulation stack and air.
  • FIELD
  • The inventions described herein relate to encapsulation stacks and light-emitting devices, such as organic light-emitting diode (OLED) devices that include the multilayered encapsulation stacks. The multilayered encapsulation stacks provide reduced total internal reflection and, therefore, improved light output efficiencies relative to conventional encapsulation stacks.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1A is a schematic diagram showing a cross-sectional view of one embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which a single high refractive index dome-shaped structure is disposed over each sub-pixel of the device. FIG. 1B is a top view of the OLED device.
  • FIG. 2 is a schematic diagram showing a cross-sectional view of a second embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which a single high refractive index cylindrical structure is disposed over each sub-pixel of the device.
  • FIG. 3 is a schematic diagram showing a cross-sectional view of one embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which multiple high refractive index dome-shaped structures are disposed over each sub-pixel of the device.
  • FIG. 4 is a schematic diagram showing a top view of another embodiment of an OLED device that includes a multilayered encapsulation stack with a composite film in which multiple high refractive index dome-shaped structures are disposed over each sub-pixel of the device.
  • FIG. 5A is a schematic diagram showing a cross-sectional view of an OLED device having a composite film at the top of its multilayered encapsulation stack.
  • FIG. 5B is a schematic diagram showing the multilayered encapsulation stack of FIG. 5A in greater detail.
  • FIG. 6 is a schematic diagram of a method of making the OLED device of FIG. 1A and FIG. 1B.
  • FIG. 7 is a schematic diagram of a method of making the OLED device of FIG. 2.
  • DETAILED DESCRIPTION
  • The devices described herein include various electronic and optoelectronic devices in which an active region of the device is encapsulated with a protective multilayered encapsulation stack. In an OLED or other electronic or optoelectronic device, the “active region” need not meet any requirement of amplification of electrical energy or transistor activity, and can refer generally to a region wherein electrical or optoelectrical activity (e.g., light emission, light absorption, or light conversion) can occur. The active region will itself generally be a multilayered structure composed of a plurality of device layers including, for example, electrodes, charge injection layers, charge transport layers, and/or light-emitting layers. Although various benefits of the encapsulation stacks are described below using a top-emitting OLED device as an illustrative example, the encapsulation stacks can be applied to other light-emitting devices, including other top-emitting lighting devices, top-emitting quantum dot (QD)-LED devices, micro-LED displays and QD-photoluminescent (PL) emissive color converters. In addition, this technology can be applied to photosensors and photocells where a high amount of light coupled into the device is advantageous.
  • A schematic diagram shown a cross-sectional view of one embodiment of an OLED device 100 that includes a multilayered encapsulation stack is depicted in FIG. 1A. A top view of the OLED device is shown in FIG. 1B. This embodiment of an OLED device includes a plurality of active regions 104 and an OLED device substrate 102. A multilayered encapsulation stack 106 is disposed over active regions 104. Multilayered encapsulation stack 106, which protects underlying active regions 104 from degradation from exposure to air and/or moisture, includes a first inorganic barrier layer 108 that suppresses the exposure of the active regions 104 to water vapor, oxygen, and/or other reactive gases present in the ambient atmosphere. Adjacent to first inorganic barrier layer 108 is a composite film 109 that includes a first domain comprising a first polymeric layer 110. First polymeric layer 110 is composed of one or more organic polymers and provides a planarization layer to planarize the encapsulation stack. In the embodiment of an OLED device depicted in FIG. 1A, multilayered encapsulation stack 106 includes a second inorganic barrier layer 108A disposed over composite film 109. In other embodiments of the encapsulation stacks, the order of the layers could be reversed, so that the composite film 109 is first fabricated, followed by the fabrication of first inorganic barrier layer 108. In such embodiments, a second planarizing polymeric layer and a second inorganic barrier layer could then be deposited, sequentially, in order to provide sufficient encapsulation for the underlying device. Thus, a modified process includes the deposition of composite film 109 directly on top of an active region of a device, followed by the deposition of a first inorganic barrier layer, followed by the deposition of a second polymeric layer, followed by the deposition of a second inorganic barrier layer. Additionally, more or fewer numbers of inorganic barrier layers and polymeric layers can be provided. For example, the encapsulation stack of FIG. 1A could have a second polymeric layer disposed on second inorganic barrier layer 108A. Active regions 104 of the OLED device of FIG. 1A may be light-emitting sub-pixels (e.g., red, green, and/or blue sub-pixels) embedded in or supported by OLED device 102 substrate. Each of these sub-pixels may include an organic light-emitting layer disposed between a first electrode (e.g., a cathode) and a second electrode (e.g., an anode). Optionally, an electron transport layer and/or an electron injection layer may be disposed between the cathode and the light-emitting layer and a hole transport layer and/or a hole injection layer may be disposed between the anode and the light-emitting layer.
  • At least one layer in the encapsulation stack is a composite film that includes a first domain formed from a first polymer and a second domain formed from a second polymer, wherein the second domain has a higher RI than the first domain and further wherein the second domain desirably has an RI that is the same as, or nearly the same as, the RI of the inorganic material of first inorganic barrier layer 108. The second domain can be a discontinuous domain that includes a plurality of sub-domains that are typically surrounded by or embedded in the first domain. For example, in the embodiment of the composite film 109 shown in FIG. 1A and FIG. 1B, the sub-domains are a plurality of dome-shaped structures 112. As a result of the reduced RI mismatch between sub-domains 112 and inorganic barrier layer 108, total internal reflection of light emitted from sub-pixels 104 at the interface between inorganic barrier layer 108 and structures 112 is reduced. Suitable RIs for sub-domains 112 will depend on the RI of the inorganic barrier layer. In some embodiments of the multilayered encapsulation stacks, the RIs of the sub-domains and the inorganic barrier layers differ by no more that ±15%, including no more than 10%, and further including no more than 5%. By way of illustration only, for an inorganic barrier layer comprising SiNx with an RI in the range from about 1.85 to about 2.2, the sub-domains may have an RI of about 1.7 or higher.
  • The material from which the higher RI domain is made can be a polymeric material comprising one or more organic polymers or a polymer composite, including a polymeric material that contains inorganic particles dispersed in a polymer matrix. Suitable polymers include acrylics, urethanes, and epoxies. Suitable inorganic particles include metal oxide particles, such as zirconium oxides, titanium oxides, hafnium oxides, zinc oxides, and mixtures of two or more thereof. Optionally, the inorganic oxide particles may be surface-functionalized with capping agents that improve their dispersibility in a polymer matrix. Such capping agents may include 2-[2-(2-9-methoxyethoxy)ethoxy] acetic acid and/or methoxy(triethyleneoxy) propyltrimethoxysilane and/or 3 methacryloyloxypropyltrimethoxysilane and/or n-octyl trimethoxysilane and/or dodecyltrimethoxysilane and/or m,p-ethylphenethyl trimethoxysilane. In some embodiments the same metal oxide is present in the higher RI domain of the composite film and the inorganic barrier layer. By way of illustration only, the high RI polymer-nanocrystal composite materials used in the nanocomposite coatings described in U.S. patent publication number 2014/0322549, the entire disclosure of which is incorporated herein by reference, could be used to form the higher RI domain in the composite films of the multilayered encapsulation stacks described herein.
  • In the embodiment of the composite film of FIG. 1A, sub-domains 112 provide a non-planar interface between the higher RI material of the sub-domains and the lower RI material of the first domain, so that they change the angle of the light reflected at that interface, such that total internal reflection is suppressed and light outcoupling and extraction is enhanced. In some embodiments of the higher RI domain materials that include particles, the particles may act as scattering centers to further reduce internal reflection and light trapping. However, for applications where light scattering is not desired, the particles may have diameters that are small enough to avoid or minimize light scattering. The sub-domains of the composite films can have a variety of shapes and sizes. For example, as shown in FIG. 1A, the sub-domains can be structures, such as hemispheres (domes) arranged in regular array or a random pattern. Once formed, the structures can be covered with a layer of the lower RI polymeric material of the first domain to form a smooth planar, or substantially planar, surface upon which the next inorganic barrier layer can be formed. Alternatively, the sub-domains can be cylinders 114 arranged in a regular array or a random pattern, as shown in FIG. 2. In this embodiment of the device, the first domain 110 surrounds cylinders 114 and the surface formed by first domain 110 and cylinders 114 provides a smooth planar, or substantially planar, surface upon which the next inorganic barrier layer 108A can be formed. The use of cylindrical structures can be beneficial because light reflected at the vertical interfaces 116 formed between cylindrical sub-domains 114 and first domain 110 can be directed toward the light-emitting surface of the device, further reducing the trapping of light in the first inorganic barrier layer 108 and/or active regions 104.
  • The dimensions and placement of the sub-domains are not strictly limited, provided that they are able to reduce the total internal reflection within the device. For example, various embodiments of the sub-domains, including the hemispherical structures, have radii in the range from 1 μm to 50 μm, inter-structure spacings (pitch) in the range from 1 μm to 100 μm, and/or heights in the range from 1 μm to 50 μm; although dimensions outside of these ranges can be used. Once formed, the sub-domains can be covered with or laterally encased in a layer of lower RI polymeric material of the first domain to form a smooth planar, or substantially planar, composite film surface upon which the next inorganic barrier layer can be formed. Alternatively, the first domain and the second domain can be formed simultaneous into a composite film having a smooth planar, or substantially planar, surface upon which the next inorganic barrier layer can be formed.
  • To avoid or reduce color bleeding and other undesirable visual effects, the sub-domains can be patterned (e.g., inkjet printed) with a resolution commensurate with the resolution of the display device. For example, in some embodiments of the multilayered encapsulation stacks, there is one sub-domain associated with each pixel or with each sub-pixel within a pixel, as illustrated in FIG. 1A, FIG. 1B, and FIG. 2. In other embodiments, the sub-domains are much smaller than the pixels or sub-pixels, such that a plurality of the sub-domains is disposed over each pixel or sub-pixel. For example, the sub-domains can be localized in clusters over each pixel or sub-pixel in a display device. This is illustrated schematically in FIG. 3, which shows a cross-sectional view of a portion of a display device including an OLED sub-pixel 304 over which an encapsulation stack 306 is disposed. Encapsulation stack 306 includes a first inorganic barrier layer 308, a composite film 309 comprising a first domain 310, a second domain comprising a plurality of dome-shaped sub-domains 312 clustered over OLED 304, and a second inorganic barrier layer 308A over composite film 309.
  • The concept of having more than one sub-domain of a composite film localized over a single sub-pixel is further illustrated in FIG. 4, which shows a top view of three sub-pixels (red (R), green (G), and blue (B)), each of which is associated with three overlying sub-domain 412 of a composite film.
  • An advantage of implementing the composite film on top of the first (i.e., lowermost) inorganic barrier layer in a multilayered encapsulation stack, rather than at the top of the encapsulation stack, is that such placement reduces the distance between the light-emitting layer of the sub-pixels and the high RI sub-domains of the composite film. This is advantageous because it helps to reduce color bleeding, which can decrease the perceived resolution, the black contrast, and/or the color gamut of the OLED display.
  • Although the composite film in the device embodiments shown in FIG. 1A, FIG. 1B, and FIG. 2, is positioned directly on the first inorganic barrier layer of the encapsulation stack, in other embodiments, the composite film can be formed on a second (or higher) inorganic barrier layer within the encapsulation stack. For example, the composite film can be placed on the top inorganic barrier layer of an encapsulation stack, as shown in the OLED device depicted in FIG. 5A and FIG. 5B. In addition, composite films can be provided on more than one inorganic barrier layer in a multilayered encapsulation stack. In still other embodiments, the composite film can be placed directly on the top surface of the underlying active regions (for example, on the top electrode of an OLED stack to provide the first layer of the encapsulation stack.
  • In embodiments in which the composite film is placed on the second or higher inorganic barrier in an encapsulation stack, all of the layers in the encapsulation stack underlying the composite film, including the polymeric planarization layers, should be made of high RI materials. In such embodiments, the underlying planarization layers can have the same material composition as the second domain in the composite film. However, the planarization layers and the second domain of the composite film need not have the same composition, provided that the planarization layers have an RI that is the same as, or nearly the same as (e.g., differing by no more than 15%), the RI of the inorganic materials of inorganic barrier layers in the encapsulation stack. By way of illustration only, for an inorganic barrier layer comprising SiNx with an RI in the range from about 1.85 to about 2.2, the high RI planarization layers may have an RI of about 1.7 or higher.
  • An embodiment of an OLED display device that includes a composite film as the final layer of an encapsulation stack is illustrated schematically in FIG. 5A. This figure is a cross-sectional view and includes the components of the active region 530 of an OLED device. These include a reflective anode 522, an organic layer stack 524, and a semi-transparent cathode 526. Over active region 530 is disposed an encapsulation stack 506 and a top protective glass layer 528. Organic layer stack 524 may include, from top to bottom, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer. The OLED device may further include a support substrate 520. In the embodiment shown here, the final layer of encapsulation stack 506 comprises a composite film 509 of the type described herein, disposed over the other, underlying encapsulation stack layers 511 (shown here as a single block for simplicity). FIG. 5B shows a more detailed cross-sectional view of encapsulation layer 506 with upper composite film 509. This composite film has a structure similar to that shown in FIG. 3, with the exception that composite film 509 is at the top of the encapsulation stack and the underlaying layers of the encapsulation stack include one of more inorganic barrier layers 507 comprising a high RI material, which may be same material from which sub-domains 512 are formed.
  • The use of a composite film that includes a high RI domain within the layers of an encapsulation stack can significantly enhance the light extraction efficiency and the integrated current efficiency of an OLED device that incorporates the film, relative to an OLED device that does not include such a film, but is otherwise the same. By way of illustration, various embodiments of the encapsulation stacks in accordance with the present teachings increase the extraction efficiency of an OLED device by at least 30% (e.g., by 30% to 40%) and the integrated current efficiency of an OLED device by at least 70% (e.g., by 70% to 100%). In addition, encapsulation stacks that include the composite films can reduce the viewing angle dependence of the emitted light, resulting in a higher quality display.
  • Examples of inorganic materials useful for fabricating inorganic barrier layers of a multilayered encapsulation stack can include, for example, various nitrides, oxides, and oxynitrides, such as one or more of silicon nitrides (SiNx), silicon oxides, Al2O3, TiO2, HfO2, and silicon oxynitrides (SiOxNy). The inorganic barrier layers can be deposited or otherwise formed over active regions and may be blanket coated (e.g., via chemical and/or physical vapor deposition) over the entirety, or substantially the entirety of the exposed surface of a substrate and active regions.
  • Polymers useful for fabricating the first and second domains of the composite films and the other polymeric planarizing layers of a multilayered encapsulation stack include various polymer materials that are curable using one or more of a thermal (e.g., bake), radiation (e.g., ultraviolet exposure), or other energy-based (e.g., electron beam) curing technique, and once cured can form a polymeric thin film and/or polymeric structure. The various polymeric layers of the encapsulation stacks can be formed using a variety of polymer deposition techniques. In some embodiments of the OLED devices, the polymeric layers of the encapsulation stack, including the composite film, are formed by inkjet printing an ink composition comprising curable monomers, oligomers, and/or polymers onto a substrate (e.g., onto an inorganic barrier layer) and curing the composition to form a polymer film. In addition, the ink compositions may include one or more crosslinking agents, polymerization initiators, and/or solvents. The polymeric planarization layers can also be made by applying the ink compositions onto a device substrate using coating techniques other than inkjet printing, followed by curing the composition to form a polymer film.
  • Examples of acrylate and methacrylate (collectively referred to herein as (meth)acrylate) monomers that can be included in an ink composition include mono(meth)acrylate monomers, di(meth)acrylate monomers and (meth)acrylate monomers of higher functionality. In various embodiments of the ink compositions, the (meth)acrylate monomers are polyethers. In various embodiments of the ink compositions, the (meth)acrylate monomers are alkoxylated aliphatic di(meth)acrylate monomers. These include neopentyl glycol group-containing di(meth)acrylates, including alkoxylated neopentyl glycol diacrylates, such as neopentyl glycol propoxylate di(meth)acrylate and neopentyl glycol ethoxylate di(meth)acrylate. Other suitable (meth)acrylate monomers include, but are not limited to: alkyl (meth)acrylates, such as methyl (meth)acrylate, ethyl (meth)acrylate, and benzyl methacrylate; cyclic trimethylolpropane formal (meth)acrylate; alkoxylated tetrahydrofurfuryl (meth)acrylate; phenoxyalkyl (meth)acrylates, such as 2-phenoxyethyl (meth)acrylate and phenoxymethyl (meth)acrylate; 2(2-ethoxyethoxy)ethyl (meth)acrylate. Other suitable di(meth)acrylate monomers include 1,6-hexanediol diacrylate, 1, 12 dodecanediol di(meth)acrylate; 1,3-butylene glycol di(meth)acrylate; di(ethylene glycol) methyl ether methacrylate; and polyethylene glycol di(meth)acrylate monomers. Other mono- and di(meth)acrylate monomers that can be included in various embodiments of the ink compositions, alone or in combination, include dicyclopentenyloxyethyl acrylate (DCPOEA), isobornyl acrylate (ISOBA), dicyclopentenyloxyethyl methacrylate (DCPOEMA), isobornyl methacrylate (ISOBMA), and N-octadecyl methacrylate (OctaM). Homologs of ISOBA and ISOBMA (collectively “ISOB(M)A” homologs) in which one or more of the methyl groups on the ring is replaced by hydrogen can also be used.
  • The multifunctional (meth)acrylate crosslinking agents desirably have at least three reactive (meth)acrylate groups. Thus, the multifunctional (meth)acrylate crosslinking agents can be, for example, tri(meth)acrylates, tetra(meth)acrylates and/or higher functionality (meth)acrylates. Pentaerythritol tetraacrylate or pentaerythritol tetramethacrylate, di(trimethylolpropane) tetraacrylate, trimethylolpropane triacrylate, and di(trimethylolpropane) tetramethacrylate are examples of multifunctional (meth)acrylates that can be used as a primary cross-linking agent. The term ‘primary’ is used here to indicate that other components of the ink compositions may also participate in crosslinking, although that is not their main functional purpose.
  • The compositions used to form the nanocomposite coatings in U.S. patent application publication number 2014/0322549 are examples of ink compositions that can be used to form the second domain of the composite films and/or any high RI planarizing layers in the encapsulation stacks. The ink compositions described in U.S. patent application numbers US 20160024322, US 2017/0062762, and US 2017/0358775 are examples of ink compositions that can be used to form the first domain of the composite films and/or other polymeric planarization layers in the multilayered encapsulation stacks.
  • With respect to properties of ink compositions applied via inkjet printing, the surface tension, viscosity, and wetting properties of the initial ink compositions should be tailored to allow the compositions to be dispensed through an inkjet printing nozzle without drying onto or clogging the nozzle at the temperature used for printing (e.g., room temperature; ca. 25° C.). By way of illustration, some embodiments of the ink compositions used to form polymeric layers have viscosities of between about 10 cP and about 28 cP (including, for example, between about 15 cP and about 26 cP) at 25° C. and surface tensions of between about 28 dynes/cm and about 45 dynes/cm at 25° C. In order to adjust or optimize the ink compositions for inkjet printing, solvents, surfactants, viscosity modifiers, and the like may be included in the ink compositions. Suitable organic solvents include esters and ethers. In addition to addressing the viscosity and surface tension of the ink, the surface energy of the surface onto which the ink composition is deposited can also be modified in order to achieve the desired ink spreading. This can be done by plasma treatment, exposure to gas containing the surface modifiers, and coating of a thin primer layer containing the surface modifiers. It is also possible to deposit these surface modifiers in a patterned fashion and thus force the ink to be pinned at a defined location on the substrate.
  • A method of making an OLED device of the type shown in FIG. 1A and FIG. 1B is illustrated schematically in FIG. 6. Initially, one or more active regions (e.g., sub-pixels) 104 are formed on device substrate 102 and first inorganic barrier layer 108 is deposited as a film over the active regions. Next, droplets of an ink composition 600 comprising the materials that make up the sub-domains of the composite film are deposited (e.g., inkjet printed) onto first inorganic barrier layer 108 over active regions 104 (panel (a)). The droplets spread on the surface and are cured to form the dome-shaped structures 112 (panel (b)). In the embodiment shown here, there is one dome-shaped structure for each active region. If the active regions comprise sub-pixels that emit different colors, the composition of the sub-domains can be independently tailored to meet the desired optical properties for the different sub-pixels. Although not shown here, pixel banks can be used to confine the spreading ink composition 600 after it is printed. Alternatively, ink composition 600 can be confined by patterning the surface of the substrate upon which it is deposited with hydrophobic and/or hydrophilic regions that control the wetting characteristics of the ink composition. Next, droplets of an ink composition 602 comprising the materials that make up the first, lower RI domain of the composite film are deposited (e.g., inkjet printed) as a coating onto first inorganic barrier layer 108 over higher RI structures 112 (panel (c)). The coating is then cured to form the first domain 110. Finally, second inorganic barrier layer 108A is deposited as a film over the first polymeric layer that constitutes the first domain of the composite film 109 (panel (d)). In another approach, the higher RI ink composition 600 is not cured before the deposition of the lower RI ink composition 602. In this case, the two ink compositions are optimized such that they do not intermix, or such that they only partially intermix, so that the outcoupling benefit of the structures in the final device is retained. In a variation to this process, the ink composition that forms sub-domain structures 112 is cured after deposition, but before the lower RI ink composition 602 that forms the first domain is deposited. In this case the interface between the two cured domains is well defined and abrupt. This approach places fewer constraints on the ink composition system because intermixing between the two ink compositions is suppressed by the curing step.
  • A method of making an OLED device of the type shown in FIG. 2 is illustrated schematically in FIG. 7. In this method, the ink composition 400 for making the higher RI structures of the sub-domains and the ink composition 602 for making the first domain are designed such that they wet the surface of first inorganic barrier layer 108 similarly to form a planar coating on the surface, but do not substantially intermix within the coating. Droplets of the ink compositions 600 and 602 can be printed (either simultaneously or sequentially) onto first inorganic barrier layer 108 without curing in between the printing steps (panels (a) and (b)) and the coating can then be cured, whereby cylindrical sub-domain structures (or features resembling cones) 114 laterally encased in a polymeric layer of the first domain 110 are formed, followed by the deposition of second inorganic barrier layer 108A (panel (c)). In this method, some intermixing between the ink compositions is allowable, provided that the intermixing zones are relatively small and the RI contrast between the two domains is preserved.
  • An industrial inkjet printing system that can be housed in an enclosure configured to provide a controlled process environment can be used for the deposition of the ink compositions onto a device substrate. Inkjet printing for the deposition of the ink compositions described herein can have several advantages. First, a range of vacuum processing operations can be eliminated, as inkjet-based fabrication can be performed at atmospheric pressure. Additionally, during an inkjet printing process, an ink composition can be localized to cover portions of an OLED substrate over and proximal to an active region, to effectively encapsulate the active region, including lateral edges of the active region. The targeted patterning using inkjet printing results in eliminating material waste, as well as eliminating additional processing typically required to achieve patterning of an organic thin film, as required, for example, by various masking techniques. The ink compositions can be printed using, for example, a printing system, such as described in U.S. Pat. No. 9,343,678.
  • The present teachings are intended to be illustrative, and not restrictive. In the Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims (20)

What is claimed is:
1. An optoelectronic device comprising:
an active region; and
a multilayered encapsulation stack disposed over the at least one active region, the multilayered encapsulation stack comprising a composite film having a first domain and a second domain, the second domain comprising a plurality of sub-domains, wherein the second domain comprises inorganic particles dispersed in a polymeric matrix and has a higher index of refraction than the first domain.
2. The optoelectronic device of claim 1, wherein the optoelectronic device is an organic light-emitting diode device and the at least one active region comprises a light-emitting pixel.
3. The optoelectronic device of claim 2, wherein the light-emitting pixel is aligned with one of the sub-domains.
4. The optoelectronic device of claim 1, wherein the multilayered encapsulation stack further comprises a plurality of inorganic barrier layers between the composite film and the active region.
5. The optoelectronic device of claim 4, wherein the composite film is adjacent to a top inorganic barrier layer of the plurality of inorganic barrier layers, the first domain has a first refractive index, the top inorganic barrier layer has a second refractive index, and the first refractive index is the same as the second refractive index.
6. The optoelectronic device of claim 4, wherein each inorganic particle comprises silicon nitride, silicon oxide, or silicon oxynitride.
7. The optoelectronic device of claim 1, wherein each sub-domain has a cylindrical or conical shape.
8. The optoelectronic device of claim 1, wherein the polymeric matrix is an acrylic matrix.
9. The optoelectronic device of claim 1, further comprising a plurality of active regions including the active region, wherein each active region is aligned with one of the sub-domains.
10. The optoelectronic device of claim 1, wherein the sub-domains are dome-shaped.
11. An optoelectronic device comprising:
a plurality of light-emitting pixels; and
a multilayered encapsulation stack disposed over the at least one active region, the multilayered encapsulation stack comprising a composite film having a first domain and a second domain, the second domain comprising a plurality of sub-domains, each sub-domain aligned with a pixel, wherein the second domain comprises oxide, nitride, or oxynitride inorganic particles dispersed in a polymeric matrix and has a higher index of refraction than the first domain.
12. The optoelectronic device of claim 11, wherein the sub-domains are localized in clusters over the pixels.
13. The optoelectronic device of claim 11, wherein the multilayered encapsulation stack further comprises a plurality of inorganic barrier layers.
14. The optoelectronic device of claim 13, wherein the composite film is between two of the inorganic barrier layers.
15. The optoelectronic device of claim 13, wherein the refractive index of the sub-domains and the refractive index of the inorganic barrier layers differ by no more than 15%.
16. The optoelectronic device of claim 11, wherein each sub-domain has a cylindrical or conical shape.
17. The optoelectronic device of claim 11, wherein the polymeric matrix is an acrylic matrix.
18. The optoelectronic device of claim 11, wherein each sub-domain is dome-shaped.
19. The optoelectronic device of claim 11, wherein the first domain comprises a first polymer and the second domain comprises a second polymer different from the first polymer.
20. The optoelectronic device of claim 11, wherein the composite film is a planarizing film.
US17/302,759 2017-12-19 2021-05-11 Light-emitting devices with improved light outcoupling Active 2039-06-25 US11793024B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US17/302,759 US11793024B2 (en) 2017-12-19 2021-05-11 Light-emitting devices with improved light outcoupling
US18/464,130 US20230422545A1 (en) 2017-12-19 2023-09-08 Light-emitting devices with improved light outcoupling

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201762607824P 2017-12-19 2017-12-19
PCT/US2018/063492 WO2019125735A1 (en) 2017-12-19 2018-11-30 Light-emitting devices with improved light outcoupling
US202016771157A 2020-06-09 2020-06-09
US17/302,759 US11793024B2 (en) 2017-12-19 2021-05-11 Light-emitting devices with improved light outcoupling

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
US16/771,157 Continuation US11043653B2 (en) 2017-12-19 2018-11-30 Light-emitting devices with improved light outcoupling
PCT/US2018/063492 Continuation WO2019125735A1 (en) 2017-12-19 2018-11-30 Light-emitting devices with improved light outcoupling

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/464,130 Continuation US20230422545A1 (en) 2017-12-19 2023-09-08 Light-emitting devices with improved light outcoupling

Publications (2)

Publication Number Publication Date
US20210328185A1 true US20210328185A1 (en) 2021-10-21
US11793024B2 US11793024B2 (en) 2023-10-17

Family

ID=66995058

Family Applications (3)

Application Number Title Priority Date Filing Date
US16/771,157 Active US11043653B2 (en) 2017-12-19 2018-11-30 Light-emitting devices with improved light outcoupling
US17/302,759 Active 2039-06-25 US11793024B2 (en) 2017-12-19 2021-05-11 Light-emitting devices with improved light outcoupling
US18/464,130 Pending US20230422545A1 (en) 2017-12-19 2023-09-08 Light-emitting devices with improved light outcoupling

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US16/771,157 Active US11043653B2 (en) 2017-12-19 2018-11-30 Light-emitting devices with improved light outcoupling

Family Applications After (1)

Application Number Title Priority Date Filing Date
US18/464,130 Pending US20230422545A1 (en) 2017-12-19 2023-09-08 Light-emitting devices with improved light outcoupling

Country Status (6)

Country Link
US (3) US11043653B2 (en)
JP (1) JP2021507448A (en)
KR (2) KR102432383B1 (en)
CN (1) CN111466037A (en)
TW (2) TW202345435A (en)
WO (1) WO2019125735A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102432383B1 (en) * 2017-12-19 2022-08-11 카티바, 인크. Light emitting device with improved light output coupling

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011121656A1 (en) * 2010-03-31 2011-10-06 パナソニック株式会社 Display panel device, and method for producing display panel device
US11043653B2 (en) * 2017-12-19 2021-06-22 Kateeva, Inc. Light-emitting devices with improved light outcoupling

Family Cites Families (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010048968A1 (en) * 2000-02-16 2001-12-06 Cox W. Royall Ink-jet printing of gradient-index microlenses
US7012363B2 (en) * 2002-01-10 2006-03-14 Universal Display Corporation OLEDs having increased external electroluminescence quantum efficiencies
US7531955B2 (en) * 2005-07-12 2009-05-12 Eastman Kodak Company OLED device with improved efficiency and robustness
EP2016620A2 (en) * 2006-04-17 2009-01-21 Omnivision Cdm Optics, Inc. Arrayed imaging systems and associated methods
US7851995B2 (en) * 2006-05-05 2010-12-14 Global Oled Technology Llc Electroluminescent device having improved light output
US7560747B2 (en) * 2007-05-01 2009-07-14 Eastman Kodak Company Light-emitting device having improved light output
US7902748B2 (en) * 2007-05-31 2011-03-08 Global Oled Technology Llc Electroluminescent device having improved light output
DE102007058453A1 (en) * 2007-09-10 2009-03-12 Osram Opto Semiconductors Gmbh Radiation-emitting device
US10103359B2 (en) * 2008-04-09 2018-10-16 Agency For Science, Technology And Research Multilayer film for encapsulating oxygen and/or moisture sensitive electronic devices
FR2936651B1 (en) 2008-09-30 2011-04-08 Commissariat Energie Atomique ORGANIC OPTOELECTRONIC DEVICE AND METHOD OF ENCAPSULATION
US20100110551A1 (en) * 2008-10-31 2010-05-06 3M Innovative Properties Company Light extraction film with high index backfill layer and passivation layer
TWI343129B (en) * 2008-11-24 2011-06-01 Ind Tech Res Inst Thin film transistor
US9184410B2 (en) * 2008-12-22 2015-11-10 Samsung Display Co., Ltd. Encapsulated white OLEDs having enhanced optical output
JP2010182449A (en) * 2009-02-03 2010-08-19 Fujifilm Corp Organic electroluminescent display device
EP2383817A1 (en) * 2010-04-29 2011-11-02 Nederlandse Organisatie voor toegepast -natuurwetenschappelijk onderzoek TNO Light-emitting device and method for manufacturing the same
US8547015B2 (en) * 2010-10-20 2013-10-01 3M Innovative Properties Company Light extraction films for organic light emitting devices (OLEDs)
EP2775327B1 (en) * 2013-03-08 2020-02-26 Samsung Electronics Co., Ltd. Film for improving color sense and method for manufacturing the same, and display apparatus including color sense improving film
US10273365B2 (en) 2013-03-15 2019-04-30 Pixelligent Technologies Llc High refractive index nanocomposite
DE102013112253A1 (en) * 2013-11-07 2015-05-07 Osram Oled Gmbh Optoelectronic component, method for operating an optoelectronic component and method for producing an optoelectronic component
US20150144928A1 (en) * 2013-11-26 2015-05-28 The Regents Of The University Of Michigan BURIED GRID FOR OUTCOUPLING WAVEGUIDED LIGHT IN OLEDs
KR101402355B1 (en) 2014-01-16 2014-06-02 (주)휴넷플러스 Organic electronic device and fabricating method thereof
DE102014105999A1 (en) * 2014-04-29 2015-10-29 Osram Opto Semiconductors Gmbh Optoelectronic semiconductor chip and method for producing an optoelectronic semiconductor chip
US9640781B2 (en) * 2014-05-22 2017-05-02 Universal Display Corporation Devices to increase OLED output coupling efficiency with a high refractive index substrate
US10115930B2 (en) * 2014-07-08 2018-10-30 Universal Display Corporation Combined internal and external extraction layers for enhanced light outcoupling for organic light emitting device
JP6620919B2 (en) * 2014-10-31 2019-12-18 国立大学法人山形大学 Organic electroluminescence lighting device
US9496523B1 (en) * 2015-06-19 2016-11-15 Universal Display Corporation Devices and methods to improve light outcoupling from an OLED array
US20170213872A1 (en) * 2016-01-27 2017-07-27 Semiconductor Energy Laboratory Co., Ltd. Display device
TWI577050B (en) * 2016-03-29 2017-04-01 華碩電腦股份有限公司 Lighting structure having patterns
CN107046047A (en) * 2016-08-19 2017-08-15 广东聚华印刷显示技术有限公司 Pixel cell of printed form electroluminescent device and its preparation method and application
CN115421329A (en) 2016-10-12 2022-12-02 科迪华公司 Display device using quantum dots and inkjet printing technology thereof
US10707274B2 (en) * 2017-10-20 2020-07-07 Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. Display panel and manufacturing method thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011121656A1 (en) * 2010-03-31 2011-10-06 パナソニック株式会社 Display panel device, and method for producing display panel device
US11043653B2 (en) * 2017-12-19 2021-06-22 Kateeva, Inc. Light-emitting devices with improved light outcoupling

Also Published As

Publication number Publication date
TW201937775A (en) 2019-09-16
CN111466037A (en) 2020-07-28
US20230422545A1 (en) 2023-12-28
WO2019125735A1 (en) 2019-06-27
US11043653B2 (en) 2021-06-22
TW202345435A (en) 2023-11-16
KR102432383B1 (en) 2022-08-11
JP2021507448A (en) 2021-02-22
KR20220118553A (en) 2022-08-25
KR20200093523A (en) 2020-08-05
US11793024B2 (en) 2023-10-17
TWI812657B (en) 2023-08-21
US20210005838A1 (en) 2021-01-07

Similar Documents

Publication Publication Date Title
US10686159B2 (en) OLED devices having improved efficiency
TWI481298B (en) Color conversion of the organic EL display
KR20210031997A (en) Light-emitting diode with optical coupling and conversion layer
US20230422545A1 (en) Light-emitting devices with improved light outcoupling
TWI821609B (en) Organic light-emitting diode (oled) display devices with uv-cured filler and manufacturing method thereof
CN103187426A (en) Organic light-emitting display apparatus and method of manufacturing the same
GB2404276A (en) Organic EL display
KR101965157B1 (en) Quantum dot hybrid organic light emitting display device and method for manufacturing the same
TWI470284B (en) Color conversion filter substrate
JP2005123089A (en) Color organic el display and its manufacturing method
WO2009098793A1 (en) Organic el display and manufacturing method thereof
KR101945499B1 (en) Quantum dot display device and method for manufacturing the same
JP2000111721A (en) Color filter and organic multicolor light emitting element
JP2006164618A (en) Display device using a plurality of organic el elements
US20070190674A1 (en) Apparatus and method for manufacturing display device
CN213425016U (en) Packaging structure
JP2015022794A (en) Resin composition for light scattering layer, light scattering layer, and organic electroluminescent device
JP6322914B2 (en) Resin composition for light scattering layer, light scattering layer, and organic electroluminescence device
CN112331799A (en) Packaging structure and manufacturing method
JP2005196075A (en) Color conversion type color display and control method for the color conversion type color display
JP2006086096A (en) Organic el display element
JP2005148475A (en) Optoelectronic apparatus and its manufacturing method, and electronic equipment
TW200803001A (en) System for displaying image and manufacturing method for organic light-emitting device

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO SMALL (ORIGINAL EVENT CODE: SMAL); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

AS Assignment

Owner name: SINO XIN JI LIMITED, HONG KONG

Free format text: SECURITY INTEREST;ASSIGNORS:KATEEVA, INC.;KATEEVA CAYMAN HOLDING, INC.;REEL/FRAME:059382/0053

Effective date: 20220307

AS Assignment

Owner name: HB SOLUTION CO., LTD., KOREA, REPUBLIC OF

Free format text: SECURITY INTEREST;ASSIGNOR:KATEEVA CAYMAN HOLDING, INC.;REEL/FRAME:059727/0111

Effective date: 20220414

STPP Information on status: patent application and granting procedure in general

Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS

STPP Information on status: patent application and granting procedure in general

Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED

STCF Information on status: patent grant

Free format text: PATENTED CASE